1. Field of the Invention
The present invention relates to an image-processing apparatus for transferring scan image data acquired in a document-reading section to an editing apparatus and receiving print data including the above-described scan image data from the editing apparatus to carry out image processing, and further relates to a method for controlling such an image-processing apparatus.
2. Description of the Related Art
It is known that image-processing apparatuses having image-reading sections determine image attributes (e.g., photography area and character area) in scan image data acquired by reading a source document and generate attribute information representing such image attributes. By applying predetermined image processing to each of the photography and character areas according to this attribute information, an optimal output for the photographic image and the character image can be acquired (refer to Japanese Patent Laid-Open No. 6-062251).
In general, scan image data acquired by reading a source document on an image-reading section is produced as image data in the bitmap format. For this reason, all characters and line images in the source document are processed as “bitmapped images.” This causes such characters and line images to suffer from jaggedness and blurring. To overcome this problem, attribute information as described above is produced and used for image processing.
There are also known systems for generating data on a computer or a server functioning as an image-editing apparatus including an image-generating application or word processor software and printing the generated data on an image-forming apparatus. Also in these systems, the image-forming apparatus generates attribute information including text, graphics, and bitmapped images based on the received data. More specifically, when an application passes data to a printer driver, the application specifies an attribute (e.g., text, graphic, or bitmapped image) for each object in the data. Based on this specification, the printer driver generates an attribute command, attaches it to the print data, and sends it to the image-forming apparatus. In the image-forming apparatus, the print data is interpreted and rasterized into bitmapped data to generate an attribute map by using the attribute command. The attribute map represents data indicating attribute information of each pixel in the rasterized image data. By applying predetermined image processing to the data using the generated attribute map, an output product where each area is subjected to optimal image processing is provided. Even if the application specifies no attribute, attribute information can be generated by applying attribute-determination processing to the rasterized image data, as described in Japanese Patent Laid-Open No. 9-284548.
Recently, overall image processing systems also have been introduced where some of the above-described systems are connected via communication networks. Such an image processing system has a function for transmitting image data acquired on an image-reading apparatus to an image-editing apparatus connected thereto via a communication member. Furthermore, the image-editing apparatus has a mechanism for subjecting the transmitted image data to image editing and transferring the edited image data to an image-forming apparatus to print the image data.
In the above-described system, when image data acquired on the image-reading apparatus is transmitted to the image-editing apparatus, no attribute information is transferred to the image-editing apparatus. In general, image data acquired on the image-reading apparatus is produced as an image file in the bitmap format. This bitmapped image file is then transferred to the image-editing apparatus, in which the bitmapped image file is edited. As a result, when an application passes the bitmapped image file to a printer driver as print data, the application specifies the attribute “bitmapped image” for the bitmapped image file. In response, the printer driver generates an attribute command indicating a bitmapped image and sends it to the image-forming apparatus. For this reason, even if the scan image data includes characters or line images, they are assigned the attribute information “bitmapped image” in the attribute map.
To overcome this shortcoming, when bitmapped image data is to be processed in a single image-forming apparatus, it is common that pixels constituting characters and line images in the bitmapped image data are subjected to image processing suitable for characters and line images, thus improving the image quality. Unfortunately, once this bitmapped image data is transmitted to an external image-editing apparatus, the attribute information is ignored. When this bitmapped image data is edited and transmitted to the image-forming apparatus as print data, characters added to the bitmapped image data by the image-editing apparatus are assigned the attribute “text”. However, since the original bitmapped image data has the attribute “bitmapped image”, characters and line images included in this bitmapped image data are subjected to image processing for the attribute “bitmapped image”. Consequently, bitmapped image data that has passed through the image-editing apparatus has often suffered from low image quality, compared with image data that has been processed in a single image-forming apparatus.
It would be possible to transfer attribute. information to the image-editing apparatus together with image data. In this case, if the image data is edited on the image-editing apparatus, the attribute information also needs to be edited. Furthermore, the definition of attribute information generated in the image-forming apparatus may differ from the definition of the attribute command generated by the application via the printer driver. For attribute information generated from scan image data, it is generally determined into which of at least two categories a pixel is classified, namely whether the pixel constitutes a character or a dot. On the other hand, attribute information specified by an application in a computer is often classified into one of text, graphic, and bitmapped image. This is partly because image data manipulated in a computer is based on the idea of “object” of the application. Furthermore, in attribute information generated from an object, the same text may be assigned different attributes depending on the character size. For example, in attribute information generated from an object, different attributes may be specified for a large-size version of a character and a small-size version of the same character. In a structure where attribute information generated in the image-forming apparatus and attribute information generated from an attribute command of print data transmitted from the image-editing apparatus to the image-forming apparatus are both used, it is impossible to determine which attribute information is appropriate information. For example, there may occur a problem such that a pixel identified as a character in attribute information generated from scan data is identified as a bitmapped image in attribute information generated according to an instruction from an application.
As described above, due to differences in the structure or definition of attribute information, it is difficult to perform image processing optimal for each attribute in image data merely by transmitting attribute information to the image-editing apparatus.